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The objective of the present study was to compare the effects of the modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine (Ingelvac PRRS MLV; Boehringer Ingelheim Animal Health, St. Joseph, MO) on European and North American PRRSV shedding in the semen of experimentally infected boars. The boars were randomly divided into six groups. Vaccinated boars shed the North American PRRSV at the rate of 10 0.1 to 10 1.0 viral genome copies per ml and 3.63 to 10 1.1 50% tissue culture infective doses (TCID 50 )/ml, respectively, in semen, whereas nonvaccinated boars shed the North American PRRSV at the rate of 10 0.2 to 10 4.7 viral genome copies per ml and 1.14 to 10 3.07 TCID 50 /ml, respectively, in semen. Vaccinated boars shed the European PRRSV at the rate of 10 0.1 to 10 4.57 viral genome copies per ml and 1.66 to 10 3.10 TCID 50 /ml, respectively, in semen, whereas nonvaccinated boars shed the European PRRSV at the rate of 10 0.3 to 10 5.14 viral genome copies per ml and 1.69 to 10 3.17 TCID 50 /ml, respectively, in semen. The number of genomic copies of the European PRRSV in semen samples was not significantly different between vaccinated and nonvaccinated challenged European PRRSV boars. The present study demonstrated that boar vaccination using commercial modified live PRRSV vaccine was able to decrease subsequent shedding of North American PRRSV in semen after challenge but was unable to decrease shedding of European PRRSV in semen after challenge.

An inter-laboratory study was performed to evaluate the performance of a method developed for the quantification of enrofloxacin in chicken meat. Liquid-liquid extraction combined with a clean-up procedure based on solid-phase extraction followed by a liquid chromatography-tandem mass spectrometric method was used by three individual laboratories. All the investigated results of calibration curves and limits of quantification were within the acceptable range for regulatory testing of enrofloxacin. The three laboratories received blind a certified reference material to analyze in triplicate and assess using statistical analysis. From the results, no statistical differences were found between the laboratories in the precision of the method. Additionally, all the results of the z-score, which is an indication of fixed interval bias criteria for accuracy from the laboratories, fell within the allowable limits (±2σ). Based on this proficiency testing by inter-laboratory comparisons, the analytical method including the sample preparation step was proven to be applicable.

To dissolve and develop the analytical methods for native polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in sanitary products, we collected sanitary napkins from Korea (K1, K2, K3), Japan (J1, J2, J3), USA (U1, U2, U3), Germany (G1, G2) and China (C1, C2), and tampons from Korea (TK), Japan (TJ1, TJ2) and USA (TU1, TU2, TU3). PCDDs and PCDFs in sanitary products were determined by HRGC/HRMS. Experimental methods consisted of comparison of extracting solvents toluene and a mixture of hexane/dichloromethane (1/1), and analysis of PCDD/Fs in sanitary products. In extracting solvent experiments with K1 and K2, octachlorinated dioxin (OCDD), hexachlorodibenzofuran (HxCDF) and octa-chlorodibenzofuran (OCDF) were detected. The recoveries of sampling standard and clean-up standard in extract of hexane/dichloromethane (1/1) were higher than extract of toluene. From the results of analysis of PCDD/Fs in sanitary napkins, no noxious materials were detected in one from Korea (K3) and three from USA (U1, U2, U3) among the tested samples with our test method. OCDD, 1,2,3,4,7,8-HxCDF and 1,2,3,6,7,8-HxCDF were detected in all the kinds of tampon tested. The concentrations of PCDD/Fs in tampon samples were similar to that in sanitary napkins.

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